Cluster casting apparatus for workpieces made of poured molten refractory material

ABSTRACT

The invention relates to an apparatus for cluster casting of workpieces made of refractory material. This apparatus comprises a bottom plate; metallic wedges cooled internally, mutually spaced, arranged circularly and radially around a cooled core resting on the bottom plate; vertical and top means confining the volumes between the wedges, said top means delimiting a central aperture communicating with said volumes and through which a molten refractory material is poured, and said wedges being movable from a position where they are in contact with the core (for the casting) to a position where they are apart from said core (for extracting the cluster). This apparatus is useful, for example, for producing plates, workpieces derived from the plate form as well as pump rotors.

United States Patent Recasens [4 1 Oct. 10,1972

[54] CLUSTER CASTING APPARATUS FOR WORKPIECES MADE OF POURED MOLTEN REFRACTORY MATERIAL [72] Inventor:

Joseph Recasens, Sorgues, France Assignee:

Filed:

Appl. No.:

LElectro-Refractaire, Paris, France May 26, 1971 [30] Foreign Application Priority Data May 26, 1970 France ..7019l02 US. Cl. ..249/8l, 249/108, 249/110, 249/123, 249/161 [58] Field ofSearch ..249/l10, 108, 81,123,161;

References Cited UNITED STATES PATENTS 11/1924 Menz ..249/108 X 3,598,175 8/1971 Olsson et al. ..249/1l0 X Primary Examiner-Robert D. Baldwin Attorney-Watson, Cole, Grindle & Watson ABSTRACT The invention relates to an apparatus for cluster casting of workpieces made of refractory material. This apparatus comprises a bottom plate; metallic wedges cooled internally, mutually spaced, arranged circularly and radially around a cooled core resting on the bottom plate; vertical and top means confining the I volumes between the wedges, said top means delimit- Int. Cl. ..B22d 27/04 ing a central aperture communicating with said volumes and through which a molten refractory material is poured, and said wedges being movable from a position where they are in contact with the core (for the casting) to a position where they are apart from said core (for extracting the cluster). This apparatus is useful, for example, for producing plates, workpieces derived from the plate form as well as pump rotors.

l0 Claim, 10 Drawing Figures P'ATENTEDnm 10 m2 SHEET 1 [IF 3 INVENTOR JOSEPH RECASENS WATSON, COLE, GRINDLE & WATSON ATTORNEYS INVENTOR JOSEPH RECAS .JS

WATSON COLE GRINDLE & WATSON ATTORNEYS P'ATENTEDW 10 m 3.697; 037

sum 3 ur a I ll '8 "4 I, $33 1 25 35% H I "\I; I I; n! I J! F/U..'IU J '6 37 I "W i /2 l35 \j/36 I I hill 7{}l I, 7; i ii! JOSEPH RECASENS WATSON COLE GRINDLE & WATSON ATTORNEYS CLUSTER CASTING APPARATUS FOR WORKPIECES MADE OF POURED MOLTEN REFRACTORY MATERIAL The invention relates to a cluster casting apparatus for workpieces made of cast molten refractory material, more particularly small plates.

Hitherto, workpieces made of cast molten refractory material were produced singly by casting the refractory material, when heated to the molten state, in sand or graphite moulds. In the case of comparatively small workpieces to be manufactured in large numbers, such as small plates, it was sometimes more economical to obtain these workpieces by sawing from a refractory block of a larger size, or by cluster casting.

In the latter case, the classic arrangement which facilitates the assembly of the moulds consists in adopting an assembly of elementary moulds in a plurality of lines and a plurality of rows supplied in series and in parallel, the whole forming the cluster. However this assembly has certain disadvantages the supply in series is not always effective, and it occurs some workpieces are insufficiently filled, whereas the geometrical arrangement of the workpieces fails to ensure identical thermic conditions for them, so that during annealing and cooling some workpieces fracture.

This wide spread phenomenon is found in the series manufacture of arch stones, bricks, small plates; etc. and its consequences are particularly serious in the case of small plates made of molten oxides which are intended, on account of their high abrasion resistance, to be used as wear proof linings for floors, silos, hoppers, crushers, etc. It is indeed well known that in this case the wear resistance of the material is directly a function of its texture, which is itself a function of the thermic cycle followed by the material during its solidification and its cooling. Classic cluster casting therefore cannot ensure for each workpiece the identical manufacturing conditions which are necessary in order to obtain a constant and regular quality in the workpieces manufactured.

It is the aim of this invention to provide a permanent apparatus making it possible to produce in a single casting operation a plurality of small plates of molten refractory material, which are treated in an identical manner thus ensuring constant quality.

The invention also aims to provide an apparatus which makes it possible for plates of variable thickness to be produced.

It is an additionnal aim of the invention to provide an apparatus which makes it possible to produce, in a single casting operation, a plurality of workpieces of refractory material of various shapes derived from the plate shape by the removal of material from the desired points.

It is a further aim of the invention to provide an apparatus which makes it possible to produce in a single casting operation, a plurality of plates of refractory material, or workpieces of various shapes derived from the plate shape, comprising means enabling them to be fixed subsequently to any desired supporting structure.

Yet another aim of the invention is to provide an ap paratus which makes it possible to produce refractory plates and workpieces of a hardened fine texture, giving them superior anti-abrasion properties.

According to the invention, this apparatus comprises a bottom plate or the like, metallic wedges cooled internally by a circulation of cooling fluid, spaced apart from each other, arranged circularly and radially about a central core, likewise cooled, and resting upon the bottom plate, vertical confining elements for the volumes existing between the wedges provided at the periphery of the latter, and top confining means of the said volumes, resting upon the wedges and delimiting a central aperture, the said wedges being radially mobile from a position in which they are in contact with the central core into a position where they are withdrawn from the said core, while the central aperture communicates with the volumes existing between the wedges.

The number of wedges must be at least three and preferably is at least 10. The said wedges may be made e.g., of copper or steel.

The bottom plate may be made of any suitable refractory material (e.g., graphite) or of metal, subject to the provision of internal cooling in the latter case.

The top confining means may consist e.g., of a removable cover, comprising two separable parts made of an appropriate material e.g., metal or graphite.

The movement of the wedges from the position in which they are in contact with the central core into a position in which they are withdrawn from the same maybe effected by any appropriate means e.g., by the use of jacks.

The communication between the central aperture and the volumes, of flat parallelepipedic general shape, existing between the wedges may be provided by using a central aperture having a larger surface than the surface of the cross section of the central core, the height of the latter being equal to or greater than that of the wedges, or else by adopting a central aperture having a surface equal to or smaller than that of the cross section of the central core, in which case the height of the latter is less than that of the wedges. The circular arrangement of the wedges ensures a uniform supply to each of the volumes between the wedges. It should be observed that these two modes of construction permit very easy regulation of the supply cross section that is to say the cross section of the communicating passage between the central aperture and the volumes between the wedges for any thickness of plates or workpieces chosen, by adopting a larger or smaller central aperture or a central core of appropriate height. This makes it possible to ensure in every case a slow supply of molten material and correct filling of the volumes between the wedges. Lastly, of course, it will also be possible to adopt acentral aperture with a surface greater than the surface of the cross section of the central core, and a central core with a height less than that of the wedges, but generally speaking such a configuration is not worth while.

As will be understood, when the wedges are in contact with the central core and the central aperture is supplied with molten refractory material e.g., through the intermediary of a feeding head or funnel the refractory material enters the volumes existing between the wedges and fills them. Since the wedges and the central core are cooled internally, the material which fills the various volumes between the wedges solidifies rapidly and forms a cast assembly comprising a cluster of small plates attached to a kind of central boss, the

shape of which corresponds to the volume delimited by the feeding head, the central aperture and the top surface of the central core. This assembly can easily be extracted from the casting apparatus after having removed the feeding head and the top confining means and having positioned the wedges in a position in which they are withdrawn from the central core. The feeding head and the top confining means may be in a plurality of parts, the opening of which occurs radially as for the wedges. Then the assembly is annealed and, after cooling, the plates are separated from the boss by sawing or by rupture. However for certain applications it may be desirable not to separate the plates from the boss and to use the entire cluster e.g., in the case of fabricating pump rotors for dense liquids, in which very considerable wear occurs by corrosion and abrasion. In this case it is desirable to have the strongest possible connection between the plates and the boss, and for this purpose the central metallic core is omitted, which means that the volumes between the wedges are supplied along the total height of the internal vertical edges of the wedges. The regulation of the distance between the wedges may then be obtained by a stop system provided on the wedges or on their driving elements. It is likewise advantageous, for this special application, to round the edges of the wedges adjacent to the central aperture so as to improve the mechanical joint between the plates and the central boss.

The above apparatus is suitable for producing plates of square or rectangular shape and of variable thickness. In fact the thickness of the plates is a function of the spacing existing between the wedges and this spacing is itself dictated by the diameter of the central core. It is therefore possible, by having central cores of different diameters, to produce plates of variable thickness with the present apparatus.

The apparatus of the invention can also be adapted for the production of workpieces having shapes derived from the plate shape e.g., by truncating the latter. This is easily achieved by arranging between the wedges, chocks or insertions of suitable shapes preventing the parallelepipedic volumes from being filled at the desired points. It is thus possible to produce workpieces having one or more truncated comers, workpieces of trapezoidal shape, or again quandrangular workpieces having different dimensions from those for which the apparatus is normally intended.

Likewise the apparatus can be adapted for the production of workpieces other than flat ones, by using wedges of appropriate shape so long as their movement by the thrust of the jacks remains possible. Thus, it is possible to cast tower shaped workpieces by using wedges, the lateral vertical faces of which have the shape of a portion of a cylinder instead of being plain, the generatrices of the cylinders being parallel to the axis of movement of the wedges so as to permit the latter.

On the other hand, the apparatus of the invention can easily be adapted to produce plates or workpieces of shapes derived from the plate shape, which comprise fixing means facilitating their subsequent assembly on any desired supporting structures. The said fixing means may consist e.g., of a simple hole provided in the plate or in the cast workpiece, enabling the latter to be fixed to the supporting structure by a bolt or similar element, or again of a metallic lug partly embedded in the plate or cast workpiece and permitting the fixation of the latter to the supporting structure, either by direct welding, or through the intermediary of a welded dowel. The hole in the plate or cast workpiece is obtained by placing in the volume delimited by two wedges, before pouring, a classic foundry core of appropriate shape. This core may be glued or otherwise fixed to the lateral vertical face of one of the wedges. Likewise the partly embedded metallic lug may be obtained by sticking by its central part to the lateral vertical face of one of the wedges a metallic piece having a plain central part which will be flush with the plate or cast workpiece, and two lateral parts inclined with respect to the central part, which will be embedded in the cast refractory material.

The apparatus of the invention is particularly well suited to the production of plates and workpieces for the construction of anti-abrasion linings, because by virtue of the cooling of the wedges, the plates and workpieces obtained have a hardened fine texture which gives them particularly worth while anti-abrasion properties.

The description hereinbelow, made with reference to the accompanying drawing, given by way of non limitative example, will fully explain how the invention can be performed.

FIG. 1 is a perspective view of an embodiment of the apparatus according to the invention, the cover being omitted FIG. 2 is a view in section along the line lI-Il of FIG. 1 of this embodiment, the cover and a feeding head being in operative position, after a casting operation FIG. 3 is a perspective view of two adjacent wedges of the apparatus of FIGS. 1 and 2 FIG. 4 is a view in partial section, corresponding to the framed portion of FIG. 2, of a variant of embodiment of the apparatus of FIGS. 1 to 3 FIG. 5 is a view in perspective illustrating the cast workpiece obtained with the apparatus of FIGS. 1 3

FIG. 6 is a view in section illustrating the cast workpiece obtained with the variant of FIG. 4

FIG. 7 is a partial view in transverse section, illustrating the production of plates having a central hole for their subsequent fixation by bolting, using the apparatus of the invention, the two adjacent wedges of the apparatus being in the closed position FIG. 8 is a view of a plate obtained with the apparatus of FIG. 7

FIG. 9 is a partial view in transverse section illustrating the production of plates having a metallic lug partly embedded for their subsequent fixation, using the apparatus of the invention, the two adjacent wedges of the apparatus being in the closed position FIG. 10 is a view of a plate obtained with the apparatus of FIG. 9.

FIGS. 1 to 3 illustrate an apparatus according to the invention. This apparatus comprises a plate shaped bottom 1 made of a refractory material e.g., graphite upon which their rests an assembly comprising a central steel core 2, of circular cross section, 200 mm high, cooled internally by a water circulation 3 4, and 12 steel wedges 5, mutually spaced, arranged circularly and radially around the core, having lateral walls 6 200 X 200 mm insize and a summit angle or equal to 30,

cooled internally by water entering through flexible pipes 7 and leaving by flexible pipes 8 respectively connected to circular water feed and discharge manifolds 9 and 10. On the exterior vertical face of one wedge in two, welded plates 11 are provided which come to rest upon the exterior vertical faces of the adjacent wedges which have no welded plates, so as to close the spaces existing between the wedges. Associated with each wedge 5 is a hydraulic jack 12, the rod 13 of which is integral with the said wedge. The manifolds 9, and the jacks 12 are attached to crowns 14 forming a chassis arranged round and at a distance from the wedges 5. On the wedges 5 their rests a removable cover 15 in two parts, 50 mm thick, formed of a refractory material such as graphite, and provided with a central aperture 16 with a greater diameter than that of the central core 2. On the edges of the aperture of the cover there rests in turn a removable feeding head 17, in two parts, formed of a refractory material such as graphite. The bottom, the wedges, the welded plates and the cover delimit volumes 18 (12 in all) of flat parallelepipedic general shape communicating with the central aperture of the cover at their upper parts in proximity of the central core and left uncovered by the cover.

It should be observed that it will be possible to adopt, as a variant, a central aperture 16 with a diameter equal to or smaller than that of the central core, provided that the latter had a smaller height than that of the wedges.

The functioning of the apparatus is as follows The cover 15 and the feeding head 17 being in position above the wedges, the mould being brought into a closed position i.e., with wedges in contact with the central core 2, by means of the jacks 12, and the water circulations being established, molten refractory material is poured into the feeding head acting as a funnel. This material fills the central aperture 16 of the cover, then enters the volumes 18 and comes to fill them. The material which fills the volumes 18 is in contact with the cooled wedges and solidifies rapidly. After solidification, the cover and the feeding head, which are both removable in two parts, are removed, the jacks 12 are operated so as to bring the mould into the open position i.e., with the wedges 5 radially distant from the central core and the solidified assembly, which assumes the form of a star shaped cluster of 12 square plates attached to a central boss, the shape of which corresponds to the interior configuration of the feeding head/central aperture assembly, is extracted.

The thickness of the plates can be adjusted with the apparatus specifically described between 0 and 20 mm by using a central core with a diameter within the range from 0 to 78 mm. The said central core in fact fixes the limit of closure of the mould and consequently the spacing of the wedges in the closed position of the mould.

When the extraction of the assembly has been performed, it is subjected to an annealing operation. The annealing conditions for the assembly extracted depend upon its composition and particularly upon the thickness of the plates.

After annealing, the plates are separated from the central boss e.g., by sawing.

By way of example, clusters of plates were prepared having thicknesses of 10 and 18 mm respectively, from a molten refractory compound having the following composition by weight ZrO, 32 percent SiO, 16 percent ALO, 51 percent Na,0 1,1 percent various impurities 0,9 percent.

The operative conditions followed are indicated in the following table The Feed Cross section is the cross section of the top surface of each volume between the wedges not covered by the cover. It is through this cross section that each volume communicates with the central apenure of the cover.

The annealing methods recommended by 6.8. Fulcher in U.S. Pat. specification No. 1,615,750, or French Pat. specification No. 619,489 are generally satisfactory for annealing the extracted assemblies.

However, for assemblies with plates 10 mm thick, natural cooling in kieselguhr produces split or even brocken workpieces. In a heatproof caisson, results are better and it is possible to take out the assemblies approximately 24 hours after they have been placed in the caisson. Good workpieces are obtained by adopting a heatproof caisson preheated to l,200 C, which is then allowed to cool naturally in approximately 24 hours, or by using a kiln at l,200 C with programmed temperature fall. It therefore appears that assemblies with thin plates (10 mm or less) have too low a calorific capacity to permit natural annealing, and that abrupt cooling on contact with the cold annealing agent (kieselguhr or silica for example) is harmful to them.

For assemblies of plates 18 mm thick, the annealing conditions are not so strict, and satisfactory results are obtained even with a natural cooling in kieselguhr or silica. This can be explained by the fact that these assemblies have a higher calorific capacity than the assemblies of 10 mm plates, which enables a greater thermic boost to be supplied for heating the annealing agent.

FIG. 4 illustrates a variant construction which differs from the mode of construction previously described solely in that it comprises a refractory disc 20, of larger diameter than the central core 2, but of smaller diameter than that of the central aperture 16, arranged on the top surface of the said core. The presence of this disc 20 makes it possible to create, as will easily be understood, weakness zones 21 at the points of attachment of the plates to the central boss, which enables the plates to be separated from the said boss by mechanical rupture without breaking their corners, and thus avoids having to perform sawing of the plates. It should be observed that the said/weakness zones could be created by other means than the disc 20 e.g., by providing beads on those parts of the edges of the wedges adjacent to the central aperture 16.

FIG. 5 illustrates the cast assembly extracted from the moulding apparatus of FIGS. 1 3. The said cast assembly comprises 12 plates 25 attached to a central boss 26 by the interior end of their top edges. It should be observed that, if the variant in which the central aperture is equal to or smaller in diameter than the central core, and the height of the latter is less than that of the wedges, has been adopted, a cast assembly would have been obtained in which the plates would have been attached to the boss by the top end of their inner vertical edges.

FIG. 6 illustrates the cast assembly extracted from the moulding apparatus of FIG. 4. The said assembly is similar to that of FIG. 5, except that it comprises weakness zones 21 at the points of attachment of the plates to the boss.

FIG. 7 illustrates the production of plates comprising a central hole permitting them to be fixed subsequently to a supporting structure by bolting. For this production, one places in the volume delimited by two adjacent wedges a foundry core 30 comprising a part 31, mm in diameter and a part 32, 14 mm in diameter, for example. The said core is 'e.g., stuck by its'end having the larger surface to the center of the lateral face 6 of one of the wedges, before performing the pouring of the molten refractory material. The total length of the core 30 is equal to the spacing of the two wedges 5 in the closed position. After pouring the mo]- ten material and extracting the cast cluster, plates are obtained which have in their center a hole 33 corresponding in shape to that of the core 30, as illustrated in FIG. 8.

FIG. 9 illustrates the production of plates having a metallic lug partly embedded in the refractory material of each plate, the said lug facilitating the subsequent fixing of the plate to a supporting structure by direct or indirect welding. For this production, one arranges in the volume delimited by two adjacent wedges 5, a metallic lug 35 having a plain central part 36 at two lateral parts 37 inclined with respect to the central part 36. The said lug 35 is stuck or fixed by magnetization, where this is possible, by its central parts to the center of the lateral face 6 of one of the wedges, before performing the pouring of the molten refractory material. After pouring the molten material and extracting the cast cluster, plates 25 are obtained in which the lugs 35 are embedded, the lateral parts 37 being embedded in the refractory material and the central part 36 lying flush with the surface of the plate, as illustrated in FIG. 10.

The conditions for pouring in the case of the variants of construction illustrated in FIGS. 7 and 9 are the same as those adopted for the productionof simple plates.

It is self-evident that the embodiments described are only examples and that it would be possible to modify them, more particularly by the substitution of equivalent technical means, without thereby departing from the ambit of the invention.

I claim:

1. Permanent apparatus for the cluster casting of workpieces made of refractory material of variable thickness, characterized in that it comprises a bottom plate, metallic wedges cooled internally by a circulation of cooling fluid, said wedges being mutually spaced and arranged circularly and radially around a central core, likewise cooled, and resting on the bottom plate,

3322 filfliieffil vlllii i'ihe g eh'iirf i fi latter and top confining means of the said volumes resting on the wedges and delimiting a central aperture, the said wedges-being radially mobile from a position in which they are in contact with the central core into a position in which they are apart from the said core, and the central aperture communicating with the volumes existing between the wedges.

2. Apparatusaccording to claim 1 characterized in that the vertical confining elements are constituted by metallic plates attached to at least some of the wedges and coming into abutment against the exterior vertical faces of wedges adjacent to the wedges to which they are attached.

' 3. Casting apparatus according to claim 1, characterized in that the top confining means consist of a removable cover provided with a central aperture.

4. Casting apparatus according to claim 1, characterized in that the mobility of each of the wedges is obtained by means of a jack.

5. Casting apparatus according to claim 1, characterized in that the central aperture has a surface greater than that of the cross section of the central core, the latter having a height equal to or greater than that of the wedges.

6.'Casting apparatus according to claim 1, characterized in that the central aperture has a surface equal to or smaller than that of the cross section of the central core, the latter having a height less than that of the wedges.

7. Casting apparatus according to claim 1, characterized in that it further comprises means to produce weakness zones at the points of attachment of the cast workpieces to the boss corresponding to the central interior volume bounded by the central aperture and the top surface of the central core.

8. Casting apparatus according to claim 7, characterized in that the said means consist of a disc arranged on the central core, said disc having a surface greater than that of the cross section of the central core, but smaller than that of the central aperture.

9. Casting apparatus according to claim 1, characterized in that the lateral vertical walls of the wedges are plain.

10. Casting apparatus according to claim 1, characterized in that the lateral vertical walls of the wedges are in the form of a portion of a cylinder. 

1. Permanent apparatus for the cluster casting of workpieces made of refractory material of variable thickness, characterized in that it comprises a bottom plate, metallic wedges cooled internally by a circulation of cooling fluid, said wedges being mutually spaced and arranged circularly and radially around a central core, likewise cooled, and resting on the bottom plate, vertical elements confining the volumes existing between the wedges provided at the periphery of the latter and top confining means of the said volumes resting on the wedges and delimiting a central aperture, the said wedges being radially mobile from a position in which they are in contact with the central core into a position in which they are apart from the said core, and the central aperture communicating with the volumes existing between the wedges.
 2. Apparatus according to claim 1 characterized in that the vertical confining elements are constituted by metallic plates attached to at least some of the wedges and coming into abutment against the exterior vertical faces of wedges adjacent to the wedges to which they are attached.
 3. Casting apparatus according to claim 1, characterized in that the top confining means consist of a removable cover provided with a central aperture.
 4. Casting apparatus according to claim 1, characterized in that the mobility of each of the wedges is obtained by means of a jack.
 5. Casting apparatus according to claim 1, characterized in that the central aperture has a surface greater than that of the cross section of the central core, the latter having a height equal to or greater than that of the wedges.
 6. Casting apparatus according to claim 1, characterized in that the central aperture has a surface equal to or smaller than that of the cross section of the central core, the latter having a height less than that of the wedges.
 7. Casting apparatus according to claim 1, characterized in that it further comprises means to produce weakness zones at the points of attachment of the cast workpieces to the boss corresponding to the central interior volume bounded by the central aperture and the top surface of the central core.
 8. Casting apparatus according to claim 7, characterized in that the said means consist of a disc arranged on the central core, said disc having a surface greater than that of the cross section of the central core, but smaller than that of the central aperture.
 9. Casting apparatus according to claim 1, characterized in that the lateral vertical walls of the wedges are plain.
 10. Casting apparatus according to claim 1, characterized in that the lateral vertical walls of the wedges are in the form of a portion of a cylinder. 